1. Technical Field
The invention relates to a hybrid cable with a central line, in particular a coaxial line, and supplementary conductors running parallel to the central line.
2. Description of the Prior Art
It is often necessary to combine a cable of a predetermined construction, for example a coaxial line, with supplementary conductors. In the presence of a central signal line, the supplementary conductors can be used for supplying power to a terminal or to an intermediate amplifier, or as supplementary signal lines. Applications include, for example, the cable of a satellite receiver antenna with a low noise biconverter requiring connection to a power supply as well as signal transmission, or coaxial cable networks for television programs to provide supplementary signal lines to enable users to simultaneously access a telephone connection.
The simplest way to manufacture a hybrid cable of this time is to insert supplementary strands in the jacket of the central line. However, especially for a small number of supplementary conductors, the shape of the cross-section of the resulting hybrid cable can deviate from the advantageous, mostly circular cross-section of the central line, making it more difficult to store and handle the cable. Moreover, the total cross-sectional area of the hybrid cable increases significantly and possibly also asymmetrically due to the required cross-section and insulation of the supplementary conductors. In the unexamined application DE 37 33 747, there is described a coaxial cable capable of transmitting with the help of supplementary conductors several signals at different potentials. However, this cable also has a complex construction and a relatively large diameter. It is also impractical because of the high costs to lay several individual cables.